The present invention relates to vacuum measuring devices and more particularly to a novel audible vacuum gauge for providing a signal representative of one or more vacuum conditions to alert the driver of the vehicle of the presence of such conditions.
Vehicles such as cars, trucks and the like consume significant amounts of fuel relative to the total amount of fuel consumed for all purposes. As a result, numerous efforts have been undertaken to design such vehicles with a view toward optimizing the economic use of fuel.
Most present day engines employ fuel supply systems having primary and secondary fuel supplies, such that, when the vacuum level drops and renders the primary system unable to supply fuel for additional engine power, the secondary system provides an added measure of fuel to accommodate the requirement for added power. The activation of the secondary system is wasteful of fuel and should normally be avoided.
Automotive experts agree that a very useful indicator of the operation of a vehicle in a fuel efficient manner is the vacuum gauge. Vacuum level is a function of engine r.p.m. and throttle opening such that vacuum level increases with increasing engine r.p.m. and increases with reductions in throttle opening. For example, when the vacuum in the engine manifold of a piston-driven engine drops below a predetermined value, this is an indication that fuel is being consumed in an inefficient manner. As a result, it is advantageous for drivers to observe their vacuum gauges with an effort to maintain the gauge reading within a preferred range to the extent that it is practical for the driver to do so, there being certain situations which, due to the prevailing conditions, such as an emergency condition or a rapid passing condition, is much more important than the short-term effort to utilize fuel in an efficient manner.
Operating a vehicle with a view towards obtaining most efficient use of the fuel consumed necessitates substantially constant observation of the vacuum gauge, and such an effort can be distracting and quite tedious. In addition, movement of the eyes away from the road is potentially dangerous. Placing an instrument upon the dashboard obstructs the view and contributes to dashboard clutter.
It thus becomes advantageous to provide an instrument for indicating the vacuum condition, which instrument is capable of providing a driver with the indication that he is either in or out of a preferred range of vacuum value without the necessity for the driver constantly diverting his attention from the road ahead in order to view the instrument.